Read each statement below carefully, and state, with reasons, if it is true or false, (a) During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body. (b) The instantaneous speed of the point of contact during rolling is zero. (c ) The instantaneous acceleration of the point of contact during rolling is zero. (d) For perfect rolling motion, work done against friction is zero. (e) A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling) motion.

What is the direction of buoyant force ?

Assertion: In projectile motion, the acceleration is constant in both magnitude and direction but the velocity changes in both magnitude and direction. Reason: When a force or accelration is acting in an oblique direction to the direction of velocity then both magnitude and direction of the velocity may be changed.

In which direction is the momentum of a moving body?

A plane body has perpendicular axes OX and OY marked on it and is acted on by following forces 5P in the direction OY, 4P in the direction OX, 10P in the direction OA where A is the point (3a, 4a) 15 P in the direction AB where B is the point (-a, a) . Express each force in the vector form & calculate the magnitude & direction of the vector sum of these forces.

Explain why friction is necessary to make the disc in Fig. 7.41 roll in the direction indicated. (a) Give the direction of frictional force at B, and the sense of frictional torque, before perfect rolling begins. (b) What is the force of friction after perfect rolling begins ?

Assertion :- When a man climbs the rope friction force acts in downward direction. Reason :- Friction force opposes relative motion to tendency of relative motion between two contact surfaces.

A particle is moving under the influence of a force which is fixed in magnitude and acting at an angle theta in the direction of motion. The path described by the particle is

The direction of weight of an object is in (upward direction, in the direction of gravitional force, in north direction)